From a4ba1c590b523a3ff7691cdffca7696301b77feb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Philipp=20G=C3=BCrtler?=
 <philipp.guertler@keenfinity-group.com>
Date: Tue, 21 Oct 2025 15:03:14 +0200
Subject: [PATCH] [typescript-fetch] Check against the typed JSON in oneOf
 serialization

---
 .../src/main/resources/typescript-fetch/modelOneOf.mustache   | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/modules/openapi-generator/src/main/resources/typescript-fetch/modelOneOf.mustache b/modules/openapi-generator/src/main/resources/typescript-fetch/modelOneOf.mustache
index 7d5c01878949..03a69ce29344 100644
--- a/modules/openapi-generator/src/main/resources/typescript-fetch/modelOneOf.mustache
+++ b/modules/openapi-generator/src/main/resources/typescript-fetch/modelOneOf.mustache
@@ -47,7 +47,7 @@ export function {{classname}}FromJSONTyped(json: any, ignoreDiscriminator: boole
         return json;
     }
     {{/-first}}
-    if (instanceOf{{{.}}}(json)) {
+    if (instanceOf{{{.}}}({{{.}}}FromJSONTyped(json, true))) {
         return {{{.}}}FromJSONTyped(json, true);
     }
     {{/oneOfModels}}
@@ -56,7 +56,7 @@ export function {{classname}}FromJSONTyped(json: any, ignoreDiscriminator: boole
     if (Array.isArray(json)) {
         if (json.every(item => typeof item === 'object')) {
     {{/-first}}
-            if (json.every(item => instanceOf{{{.}}}(item))) {
+            if (json.every(item => instanceOf{{{.}}}({{{.}}}FromJSONTyped(item, true)))) {
                 return json.map(value => {{{.}}}FromJSONTyped(value, true));
             }
     {{#-last}}